Proximal Junctional Degeneration and Failure Modes: A Novel Classification and Clinical Implications.

STUDY DESIGN: Case-control study. OBJECTIVE: To introduce a classification system that will include the major types of degenerative changes and failures related to the proximal junction, and to determine the clinical course and characteristics for the different types of proximal junctional degeneration (PJD). SUMMARY OF BACKGROUND DATA: Proximal junctional kyphosis (PJK) and failures are well recognized after adult spinal fusion, however, a standardized classification is lacking. METHODS: The proposed system identified four different patterns of PJD: Type 1 (multi-level symmetrical collapse), Type 2 (Single adjacent level collapse), Type 3 (fracture) and Type 4 (spondylolisthesis). A single center database was reviewed from 2018 to 2021. Patients ≥18 years of age, who underwent posterior spinal fusion of ≥3 levels with an upper instrumented vertebral level between T8-L2, and a follow-up of ≥2 years were included. Radiographic measurements, revision surgery and time to revision were the primary outcomes. RESULTS: 150 patients were included with a mean age of 65.1 (±9.8) years and a mean follow-up of 3.2 (±1) years. 69 patients (46%) developed significant degenerative changes in the proximal junction, and were classified accordingly. 20 (13%) were Type 1, 17 (11%) were Type 2, 22 (15%) were Type 3 and 10 (7%) were Type 4. Type 3 had a significantly shorter time to revision with a mean of 0.9 (±0.9) years. Types 3 and 4 had greater preoperative sagittal vertical axis, and Types 1 and 3 had greater final follow-up lumbar lordosis. Bone density measured by Hounsfield units showed lower measurements for Type 3. Types 1 and 4 had lower rates of developing PJK. Type 1 had the lowest revision rate with 40% (types 2, 3 and 4 were 77%, 73% and 80%, respectively, P=0.045). CONCLUSION: This novel classification system defines different modes of degeneration and failures at the proximal junction, and future studies with larger sample sizes are needed for validation. LEVEL OF EVIDENCE: 3.

Quantitative Romberg on a Force Plate: Objective Assessment Before and After Surgery for Cervical Spondylotic Myelopathy.

STUDY DESIGN: Longitudinal Observational Cohort. OBJECTIVES: The purpose of this study was to evaluate the utility of Quantitative Romberg measurements as pre- and post-op balance outcome measures. SUMMARY OF BACKGROUND DATA: Cervical Spondylotic Myelopathy (CSM) is characterized by balance deficiencies produced by impaired proprioception. Evaluation is subjective and binary physical exam findings lack the precision to assess postoperative outcome improvement. METHODS: CSM patients were prospectively enrolled to undergo pre- and postoperative Quantitative Romberg tests on a force plate to record center of pressure (COP) motion for 30 seconds with eyes open followed by eyes closed. Revision cases were excluded. Kinematics of COP movement parameters were compared between pre- and postoperative state for each patient. RESULTS: Twenty-seven CSM patients were enrolled and completed both pre/post testing. Mean age was 60.0 years with 13 (48%) males, 9 (33%) smokers. Mean number of surgical levels was 2.48. The minimum mean follow-up was six months. There was a statistically significant improvement in eyes closed after surgery compared to pre-operative for total COP motion (523.44 cm vs. 387.00 cm, P<0.001), average sway speed (17.41 cm/s vs. 13.00 cm/s, P<0.001) and total lateral COP motion (253.44 cm vs. 186.70 cm, P<0.001). There was no statistically significant improvement in mJOA (13.29 vs. 14.29, P=0.28). CONCLUSION: CSM balance findings on Quantitative Romberg testing significantly improves postoperatively in patients with CSM. These findings support this testing as representative of proprioceptive balance deficiencies seen in CSM. Quantitative Romberg may be used as an objective measure of clinical outcome and assist in stratification of surgical interventions, surgery timing and technique.

Neck Disability Index, short form-36 physical component summary, and pain scales for neck and arm pain: the minimum clinically important difference and substantial clinical benefit after cervical spine fusion.

BACKGROUND CONTEXT: The Neck Disability Index (NDI), the short form-36 (SF-36) physical component summary (PCS), and pain scales for arm and neck pain are increasingly used to evaluate treatment effectiveness after cervical spine surgery. The minimum clinically important difference (MCID) is a threshold of improvement that is clinically relevant to the patient. However, the true goal is to provide the patient with a substantial clinical benefit (SCB). PURPOSE: This study determines the MCID and SCB using common anchor-based methods for NDI, PCS, and pain scales for arm and neck pain in patients undergoing cervical spine fusion for degenerative disorders. STUDY DESIGN/SETTING: The study setting is a longitudinal cohort in a multisurgeon spine specialty clinic. PATIENT SAMPLE: The sample comprises 505 patients who underwent a cervical fusion for degenerative spine conditions and who have prospectively collected outcome scores with a minimum 1-year follow-up. OUTCOME MEASURES: The outcome measures of the study were NDI, SF-36, and numeric rating scales for arm and neck pain. METHODS: The MCID and SCB values for NDI, PCS, and pain scales for arm and neck pain were determined using receiver operating characteristic (ROC) curve analysis with the Health Transition Item of the SF-36 as an anchor. The Health Transition Item asks a patient "Compared to one year ago, how would you rate your health in general now?" with answers ranging from "Much Better," "Somewhat Better," "About the Same," "Somewhat Worse," to "Much Worse." An ROC curve was constructed for each measure. The ROC curve-derived MCID was the change score with equal sensitivity and specificity to distinguish the "Somewhat Better" from the "About the Same" patients. The ROC curve-derived SCB was the change score with equal sensitivity and specificity to distinguish the "Much Better" from the "Somewhat Better" patients. Distribution-based methods including the standard error of the mean and the minimum detectable change were also used to calculate MCID. RESULTS: The calculated MCID is 7.5 for the NDI, 4.1 for SF-36 PCS, and 2.5 for arm and neck pain. The calculated SCB is 9.5 for the NDI, 6.5 for SF-36 PCS, and 3.5 for arm and neck pain. CONCLUSIONS: Patients with an eight-point decrease in NDI, a 4.1-point increase in PCS, and a three-point decrease in arm or neck pain can detect a minimally clinically important change. Patients with a 10-point decrease in NDI, a 6.5-point increase in PCS, and a four-point decrease in arm or neck pain can detect an SCB after cervical spine fusion.

Perioperative complications of recombinant human bone morphogenetic protein-2 on an absorbable collagen sponge versus iliac crest bone graft for posterior cervical arthrodesis.

STUDY DESIGN: Retrospective evaluation of perioperative complications with recombinant human bone morphogenetic protein-2 on an absorbable collagen sponge (rhBMP-2/ACS) versus iliac crest bone graft (ICBG) for instrumented posterior cervical fusion. OBJECTIVE: To determine the risk of perioperative complications using rhBMP-2/ACS for posterior cervical fusion compared with ICBG. SUMMARY OF BACKGROUND DATA: There is substantial use of rhBMP-2/ACS as a bone graft substitute for spine fusions outside the Food and Drug Administration-approved indication of anterior lumbar interbody fusion. Efficacy for inducing fusion and avoidance of iliac crest donor-site complications are frequent reasons cited for its use. Previous studies have reported use in the anterior lumbar spine, the posterior lumbar spine, and in the anterior cervical spine. Site-specific perioperative complications that have been reported, especially with use in the anterior cervical spine, confirm that safety and efficacy should be established for specific anatomic sites and clinical indications. METHODS: From July 2002 to February 2005, a consecutive series of patients who underwent instrumented posterior cervical fusion were identified. Patients received either rhBMP-2/ACS or ICBG based on the discretion of the surgeon. Patients were excluded if they had a preoperative diagnosis of trauma, tumor, or infection, or if they underwent a concomitant anterior procedure. Seventy-seven patients met the inclusion criteria. Forty-one of these patients received rhBMP-2/ACS and 36 received ICBG. Standard demographic, surgical, and perioperative complication data were collected from the medical records. RESULTS: There were no significant differences in age, gender distribution, smoking status, number of surgical levels, blood loss, operative time, or length of stay between the 2 groups. There were more posterior cervical wound complications requiring treatment in the rhBMP- 2/ACS group (6, 14.6%) versus the ICBG group (1, 2.8%), although this was not statistically significant (P = 0.113). One patient (2.8%) in the ICBG group had a wound complication at the iliac crest donor site. Additional perioperative complications were noted in 3 patients (7.3%) in the ICBG group and none in the rhBMP-2/ACS group. CONCLUSION: The higher incidence of posterior cervical wound complications in the rhBMP-2/ACS group, although not statistically significant, may be related to an inflammatory response to rhBMP-2. This potential risk must be weighed against the elimination of donor-site complications associated with ICBG harvesting, and considered in light of ultimate clinical outcome. Additional studies are needed to clarify this issue, as well as to determine optimal dosing and carrier for usage in the posterior cervical spine.

Are preoperative health-related quality of life scores predictive of clinical outcomes after lumbar fusion?

STUDY DESIGN: Prospective longitudinal cohort. OBJECTIVE: This study evaluated the effect of preoperative Mental Component Summary (MCS), preoperative Physical Component Summary (PCS), preoperative Oswestry Disability Index (ODI), back pain predominance, body mass index (BMI), age, smoking status, and workers' compensation on health-related quality of life after lumbar fusion. These factors were selected as they are readily available and may influence a surgeon's decision-making process. SUMMARY OF BACKGROUND DATA: Measures of health-related quality of life are increasingly used to evaluate treatment effectiveness. However, their use as a predictive tool to determine which patients will improve has been limited. METHODS: The Short Form 36 (SF-36) and ODI were collected before surgery and two years after surgery in 489 patients undergoing lumbar fusion for degenerative disorders. Linear regression modeling was used to determine the effect of preoperative MCS, preoperative PCS, preoperative ODI, back pain predominance, BMI, age, smoking status, and workers' compensation on the change in ODI and change in SF-36 PCS two years after lumbar fusion. RESULTS: Patients with better preoperative MCS (P = 0.008) and worse preoperative ODI scores (P < 0.0001) achieved greater ODI improvement. Workers' compensation patients did significantly worse (P = 0.03). Patients with better preoperative MCS (P = 0.0004), better preoperative PCS (P = 0.0155), and worse preoperative ODI scores (P = 0.0210) achieved greater PCS improvement. Those on workers' compensation had lower changes in PCS, an effect that was nearly significant (P = 0.0644). There were no significant correlations between PCS and ODI improvement and back pain predominance, BMI, age, and smoking status. Attempts at determining threshold values for MCS, PCS, and ODI that are predictive of a patient achieving minimum clinically important difference for PCS and ODI were unsuccessful. CONCLUSION: Patients with good preoperative MCS and poor preoperative ODI scores who are not on workers' compensation are more likely to improve after lumbar fusion. Threshold values for MCS, PCS, and ODI predictive of a patient achieving minimum clinically important difference for PCS and ODI could not be determined.

RhBMP-2 versus iliac crest bone graft for lumbar spine fusion in patients over 60 years of age: a cost-utility study.

STUDY DESIGN: Randomized clinical trial. OBJECTIVE: To perform a cost-utility analysis using actual cost data from a randomized clinical trial of patients over 60 years old who underwent posterolateral fusion using either rhBMP-2/ACS or iliac crest bone graft (ICBG). SUMMARY BACKGROUND DATA: Bone morphogenetic protein has been shown to be an effective bone graft substitute for spine fusion. However, a clinical trial-based economic analysis of rhBMP-2/ACS compared with iliac crest bone graft has not been done. METHODS: Patients over 60 years old requiring decompression and posterolateral fusion were randomized to rhBMP-2/ACS (n = 50) or ICBG (n = 52). A dedicated hospital coder and research nurse tracked each patient to determine direct costs of inpatient care and all postoperative healthcare encounters up to 2 years after surgery. Preoperative and 2-year-postoperative SF-6D utility scores for each patient were determined. A decision tree was created, which included the probability of complications, need for additional treatments and revision surgery; and the costs associated with initial surgery and treatment for complications and additional treatment for continued spine symptoms; and utility scores. RESULTS: The mean total 2-year cost for care (excluding complication and additional spine treatment costs) was $34,235 in the ICBG group and $36,530 in the rhBMP-2/ACS group. For the entire group, the mean cost to treat a major complication was $10,888, the cost of revision surgery for nonunion was $46,852, and additional treatment for spine-related events was $5892. In the ICBG group, 8 patients had complications; 20 had additional interventions, 5 of whom required revision for nonunion. In the rhBMP-2/ACS group, 6 patients had complications, 10 had additional interventions, and 1 required revision for nonunion. The cost of using rhBMP-2/ACS was $39,967 with a 0.11 mean improvement in SF-6D; and for ICBG the cost was $42,286 with a mean improvement of 0.10 in SF-6D. CONCLUSION: There are more complications, increased need for additional treatment and revision surgery in patients over 60 years old receiving ICBG compared with rhBMP-2/ACS. This may account for higher costs and lower improvements in utility seen in patients receiving ICBG compared with rhBMP-2/ACS in this study population.

Lumbar fusion outcomes stratified by specific diagnostic indication.

BACKGROUND: One of the primary difficulties in evaluating the effectiveness of lumbar fusion is that, with the exception of spondylolisthesis, specific diagnostic indications for surgery are poorly defined. Diagnostic specificity beyond the symptom of low back pain or the presence of lumbar degeneration needs to be delineated such that outcomes data can be effectively translated into clinical decision making or evidence-based guidelines. PURPOSE: The purpose of this study was to report on prospectively collected clinical outcome measures, stratified by diagnosis, among a series of patients with lumbar degenerative disease whose treatment included lumbar spine fusion. STUDY DESIGN: Demographics, diagnostic categorization, and clinical outcome measures were prospectively collected by six spine surgeons at a single tertiary spine center, as part of the surgeons' standard clinical practice. PATIENT SAMPLE: Four hundred and twenty-eight patients were enrolled in the study and complete 1- and 2-year Health-Related Quality of Life (HRQOL) data were available in 327 patients whose treatment included decompression and posterolateral lumbar fusion. OUTCOME MEASURES: The Oswestry Disability Index (ODI), Short Form-36 (SF-36), numeric rating scales for back pain and leg pain. METHODS: Preoperative diagnosis was classified, in the primary surgical cases, as disc pathology, spondylolisthesis, instability, stenosis, or scoliosis. In revision cases, the diagnosis was classified as nonunion, adjacent level degeneration, or postdiscectomy revision. Patient-reported outcomes at 1 and 2 years post-op were assessed based on diagnostic stratification. Statistical evaluation of clinical outcome was performed for both mean net change in outcome scores and the percentage of patients reaching a minimum clinically important difference (MCID) threshold for each outcome measure. RESULTS: Preoperative diagnosis was spondylolisthesis (n=80), scoliosis (n=17), disc pathology (n=33), instability (n=21), stenosis (n=46), postdiscectomy revision (n=67), adjacent level degeneration (n=40), or nonunion (n=23). Evaluation of 2-year post-op HRQOL measures by diagnostic subgroup revealed the most substantial improvement in ODI score for patients with spondylolisthesis (22.7 points) and scoliosis (21.2 points). Patients with the diagnosis of disc pathology (16.2 points), postdiscectomy revision (14.0 points), instability (12.7 points), stenosis (10.6 points), and adjacent level degeneration (9.5 points) demonstrated a progressively smaller magnitude of ODI improvement. The least ODI improvement at 2 years after surgery was seen in patients with nonunion of a prior fusion (5.5 points). The percentage of patients reaching MCID for ODI at 2 years post-op ranged from 71.0% in the spondylolisthesis subgroup to 34.8% in the nonunion subgroup. The greatest SF-36 physical component score improvement at 2-year follow-up was seen in patients with disc pathology (7.9 points) and spondylolisthesis (7.7 points), followed by scoliosis (6.6 points) and stenosis (6.5 points), instability (5.6 points), postdiscectomy revision (5.3 points) nonunion (3.1 points) and adjacent level degeneration (2.5 points). No significant changes from Year 1 to Year 2 were noted in any of the subgroups. For SF-36 physical component score, percentage of patients reaching MCID ranged from 63.6% in the disc pathology subgroup to 25% in the nonunion subgroup. CONCLUSIONS: This study supports the concept that added diagnostic specificity is a critical component in building an improved evidence base for lumbar fusion surgery. The magnitude of HRQOL improvement was not equal among diagnostic subgroups. The percentage of patients reaching an MCID level of improvement was also significantly influenced by diagnostic stratification. Without diagnostic specificity for entities beyond spondylolisthesis, the absence of well-defined study populations will continue to limit our ability to move toward evidence-based decision making.

Use of cervical collar after single-level anterior cervical fusion with plate: is it necessary?

STUDY DESIGN: Randomized clinical trial. OBJECTIVE: This study is evaluates whether the use of a cervical collar after single-level anterior cervical fusion with plating increases the fusion rate and improved clinical outcomes. SUMMARY OF BACKGROUND DATA: Plates limit motion between the graft and the vertebra in anterior cervical fusion. Still, the use of cervical collars after instrumented anterior cervical fusion is widely practiced. METHODS: Patients enrolled in an FDA-regulated, multicenter trial in 32 centers treated with single-level decompression and arthrodesis using allograft and an anterior cervical plate were included in the analysis. Patients were divided into Braced and Nonbraced groups regardless of type of brace. SF-36, Neck Disability Index (NDI), Numerical Rating Scales (0-100) for neck and arm pain were determined before surgery, 1.5, 3, 6, 12, and 24 months after surgery. Fusion was assessed by independent radiologists at 6, 12, and 24 months after surgery using upright AP, lateral, and flexion-extension views. Fusion success was defined as the presence of bridging trabecular bone, angulation of less than or equal 4 degrees on flexion-extension radiographs; and absence of radiolucencies. RESULTS: Two hundred fifty-seven patients were included in the analysis, 149 were braced and 108 were not. Demographic characteristics and baseline outcome measures of both groups were similar. There was also no statistically significant difference in any of the clinical measures at baseline except for SF-36 Physical Component Summary score. The SF-36 Physical Component Summary, NDI, neck, and arm pain scores were similar in both groups at all time intervals and showed statistically significant improvement when compared with preoperative scores. There was no difference in the proportion of patients working at any time point between the Braced and Nonbraced group. Independent radiologists reported higher rates of fusion in the Nonbraced group over all time intervals, none of which were statistically significant. CONCLUSION: Our results show that the use of a cervical brace does not improve the fusion rate or the clinical outcomes of patients undergoing single-level anterior cervical fusion with plating.

Adverse events in patients re-exposed to bone morphogenetic protein for spine surgery.

STUDY DESIGN: Case series from a single spine specialty clinic. OBJECTIVE: This study analyzed wound related or anaphylactic adverse events in patients re-exposed to rhBMP-2. SUMMARY OF BACKGROUND DATA: The use of recombinant bone morphogenetic protein (rhBMP-2) as a bone graft substitute is increasing. There is concern that re-exposing patients to rhBMP-2, might result in a hyper-inflammatory response causing wound problems or an allergic reaction. METHODS: Ninety-six patients who had at least 2 spine surgeries using rhBMP-2 (Infuse, Medtronic Sofamor Danek, Memphis, TN) were identified. Anteroposterior surgeries, surgeries for infection and trauma were excluded. Demographic and operative data were collected from review of medical records. Surgeries were classified into primary, revision same approach and revision different approach. Logistic regression was used to control for variables associated with increased risk of complications. RESULTS: During the first exposure there were 90 primary fusions and 6 revisions with 2 wound infections requiring debridements and 9 minor wound problems. During the second exposure there were 25 primary fusions, 50 same approach first revisions, 16 different approach first revisions, 1 same approach second revision and 4 different approach second revisions. There were 5 wound infections, 11 minor wound problems and no allergic reactions. There was no significant difference in the number of complications between the first and second surgeries or between patients who had a second primary surgery, a revision through the same approach or through a different approach. There were no wound problems or allergic reactions among twelve patients who had a third surgery with rhBMP-2. CONCLUSION: Multiple exposures to rhBMP-2, whether for a second primary surgery, revision through the same approach or revision through a different approach does not increase the risk of a wound infections/problems or result in clinically detectable allergic reactions.

The perioperative cost of Infuse bone graft in posterolateral lumbar spine fusion.

BACKGROUND CONTEXT: There is mounting evidence supporting the efficacy of bone morphogenetic protein (BMP) for both anterior interbody and posterolateral lumbar fusion. However, the relative cost of BMP remains an important concern for physicians, hospitals, and payers. PURPOSE: The purpose of this study is to report on the perioperative costs for patients treated with rhBMP-2 as compared with an iliac crest bone graft (ICBG) supplemented with graft extenders. STUDY DESIGN/SETTING: A prospective randomized controlled trial of rhBMP-2/ACS (Infuse Bone Graft; Medtronic Sofamor Danek, Memphis, TN) versus ICBG+/-graft extender for lumbar spine fusion in patients over 60 years old. PATIENT SAMPLE: One hundred two patients over 60 years old who required a posterolateral lumbar spine fusion randomized between receiving rhBMP-2/ACS or ICBG. OUTCOME MEASURES: All health-care costs over the first 3 months after surgery. METHODS: As part of a prospective randomized trial of rhBMP-2/ACS versus ICBG+/-graft extender for lumbar spine fusion, all costs over the first 3 months after surgery were directly recorded by a dedicated coder funded by Norton Healthcare, Louisville, KY. A dedicated research nurse also followed all patients throughout their hospital stay and posthospitalization recovery to identify any adverse events or additional outpatient medical care. RESULTS: Fifty patients received rhBMP-2/ACS and 52 underwent ICBG harvest. The mean hospital cost for the index admission was $24,736 for the rhBMP-2/ACS group and $21,138 for the ICBG group. Mean inpatient physician costs were $5,082 in the rhBMP-2/ACS group and $5,316 in the ICBG group. Costs associated with posthospital rehabilitation averaged $4,906 in the rhBMP-2/ACS group versus $6,820 in the ICBG group. Total payer expenditure for the 3-month perioperative period averaged $33,860 in the rhBMP-2/ACS group and $37,227 in the ICBG group. CONCLUSIONS: The hospital carries the cost burden associated with the utilization of rhBMP-2/ACS. In contrast, the payer in a Diagnosis-Related Group (DRG) model achieves a net savings, based primarily on the decreased payment for inpatient rehabilitation, but also on decreased hospital reimbursement, physician costs, and other outpatient services.

Clinical outcomes in older patients after posterolateral lumbar fusion.

BACKGROUND CONTEXT: Older patients are often advised that their age is a contraindication to lumbar fusion surgery. There is, however, limited available data to support or contradict this assertion. Although prior studies of surgical treatment for lumbar degenerative disease suggest that older patients obtain symptomatic pain relief, an evaluation of fusion outcomes based on modern Health-Related Quality of Life (HRQOL) measures is lacking. PURPOSE: The purpose of this study was to document clinical outcomes based on standardized HRQOL measures in patients over 65 years of age treated by lumbar decompression and fusion surgery. DESIGN/SETTING: This study was a retrospective review of prospectively collected patient reported outcomes data. PATIENT SAMPLE: Ninety-seven consecutive patients over 65 years of age treated by lumbar decompression and fusion between 2000 and 2004 were enrolled in a prospective health status outcomes protocol. Eighty-five patients (88%) had complete data at a minimum 2-year follow-up. OUTCOME MEASURES: Medical Outcomes Study Short Form 36v.2 (SF-36), Oswestry Disability Index (ODI), numeric rating scales (NRS) back and leg pain scores. METHODS: Patients over 65 years of age treated by lumbar fusion were evaluated based on HRQOL measures at a minimum of 2 years postoperatively. Variables including history of prior surgery and occurrence of a perioperative complication were evaluated. A comparison group of patients 50 to 64 years of age was also analyzed. RESULTS: In patients over 65 years old, mean improvement of 6.21 points in SF-36 Physical Composite Score and 5.75 points in SF-36 Mental Composite Score was observed. There was a mean 16.38-point improvement in ODI, 3.08-point improvement in back pain NRS, and 2.65-point improvement in leg pain NRS. SF-36 subscale scores showed improvement for all parameters except general health, where there was a small but statistically significant decline. There was no difference in outcomes at 2 years postoperatively based on the occurrence of a perioperative complication. Patients undergoing a primary lumbar surgical procedure had consistently better outcomes than patients undergoing a revision procedure. CONCLUSIONS: The results of this study support the efficacy of lumbar decompression and fusion in selected patients over 65 years of age. Occurrence of a perioperative complication did not adversely affect clinical outcome. Patients undergoing a revision procedure should be counseled with regard to the more limited benefits seen with revision surgery.

Lumbar degenerative classification study.

The purpose of this study was to develop and validate a classification of indications for fusion in lumbar degenerative disease. Nineteen spine surgeons reviewed a series of 32 case histories and selected the indication for fusion based on an outlined classification system. To determine the degree of interrater variability, K coefficients were calculated (K for all 32 cases, 0.63). Results from this study show the significant difficulty in classifying the indication for fusion in lumbar degenerative disease. The level of the 19 surgeons' agreement regarding surgical indication was only moderate, despite a study design that eliminated controversial issues of patient and procedure selection. To a significant extent, the difficulty in classifying indication for fusion underlines the importance of the process. If we cannot agree on why a specific patient is selected for fusion, it is then impossible to accurately compare outcomes for a given disease process or surgical technique. For this reason, an ongoing effort to refine nomenclature and classification is necessary.

Treatment of anterior cervical pseudoarthrosis: posterior fusion versus anterior revision.

BACKGROUND CONTEXT: Posterior fusion has been advocated as the most effective treatment of anterior cervical pseudoarthrosis. Authors cite the benefits of increased stability and avoiding the risk of dissection through anterior scar tissue. Despite these advantages, posterior fusion is a more extensive procedure from the standpoint of perioperative and postoperative recovery. PURPOSE: The objective of this study is to compare the results of posterior fusions to revision anterior fusions for repair of anterior cervical pseudoarthrosis. STUDY DESIGN/SETTING: This is a retrospective case series from a single institution. PATIENT SAMPLE: 120 patients with nonunion documented on flexion-extension radiographs, computed tomography (CT) scan or tomograms after an anterior cervical discectomy and fusion with at least 2-year follow-up. OUTCOME MEASURES: Surgical data, status of fusion, complications, and any revision surgeries. METHODS: Hospital and office records were reviewed to determine demographic data, surgical data, status of fusion, and any revision surgeries. Nonunion was confirmed during surgery. RESULTS: Of the 120 patients included in the study, 27 had repeat anterior procedures and 93 had posterior procedures. The proportion of smokers, the number of surgical levels, and the average time to revision in each group were similar. The average operative time for the anterior revision surgery was 134.9 minutes (range 49 to 232 minutes) with an estimated blood loss of 102.7 cc. In the posterior revision surgery the average operative time was 138.9 minutes (range 35 to 356 minutes) and an average estimated blood loss of 282.1 cc. The patients in the anterior revision group had an average hospital stay of 2.3 days (1 to 5 days), whereas those in the posterior revision group had an average hospital stay of 4.4 days (3 to 8 days). There was a 4% complication rate in the anterior revision group and an 8% complication rate in the posterior revision group. Twelve of 27 patients (44%) in the anterior revision group, and 2 of 93 patients in the posterior revision group required a second revision surgery for persistent nonunion. CONCLUSIONS: Based on these results, posterior fusion is more effective in treating anterior cervical pseudoarthrosis than revision anterior fusion. The higher fusion rate and lower incidence of repeat revision surgery offset the increased blood loss and longer recovery time associated with posterior cervical fusions.

Initial fusion rates with recombinant human bone morphogenetic protein-2/compression resistant matrix and a hydroxyapatite and tricalcium phosphate/collagen carrier in posterolateral spinal fusion.

STUDY DESIGN: Prospective, randomized, unblinded study of iliac crest bone graft (ICBG) versus recombinant human bone morphogenetic protein-2/compression resistant matrix (rhBMP-2/CRM)in a posterolateral instrumented fusion procedure. OBJECTIVES: Document initial radiographic characteristics, based on computed tomography, with rhBMP-2/CRM for posterolateral fusion at 6 and 12-month intervals. SUMMARY OF BACKGROUND DATA: As the acceptance of INFUSE bone graft as an ICBG replacement becomes more widespread, surgeons have begun to study applications for rhBMP-2 in posterior spinal fusion. Preclinical studies have examined variables including carrier composition, rhBMP-2 concentration, and rhBMP-2 dose. Pilot studies have been performed with encouraging initial results. METHODS: Patients with single level lumbar degenerative disease were enrolled in a randomized study of ICBG versus rhBMP-2/CRM in a posterolateral instrumented fusion procedure. Computed tomography scans at 6 and 12 months were graded as demonstrating no fusion (grade 1), partial or limited unilateral fusion (grade 2), partial or limited bilateral fusion (grade 3), solid unilateral fusion (grade 4), or solid bilateral fusion (grade 5). RESULTS: At our institution, 74 patients (38 rhBMP-2/CRM, 36 ICBG) reached minimum 1-year follow-up and were included in this analysis. Mean fusion grade (scale1-5) at 6 months after surgery was 4.35 in the rhBMP-2/CRM group versus 3.09 in the ICBG group (P < 0.0001). At 1 year after surgery mean fusion grade was 4.62 in the rhBMP-2/CRM group versus 3.77 in the ICBG group (P < 0.0023). CONCLUSIONS: These early results are encouraging and suggest a more rapid incorporation and development of the fusion mass with rhBMP-2/CRM than iliac crest autograft in a single level posterior instrumented fusion.

Treatment of pyogenic vertebral osteomyelitis with anterior debridement and fusion followed by delayed posterior spinal fusion.

STUDY DESIGN: Case series. OBJECTIVES: The results of surgical treatment of osteomyelitis with anterior debridement and fusion followed by delayed posterior stabilization and fusion are presented. METHODS: Forty-two patients with vertebral osteomyelitis are presented. There were 5 cervical, 12 thoracic, 1 thoracolumbar, 19 lumbar, and 5 lumbosacral lesions. The most frequently identified organism was Staphylococcus aureus. Most patients had significant comorbidities, including diabetes, or were immunocompromised. Ninety percent had elevated erythrocyte sedimentation rates and C-reactive proteins, while white blood cell counts were less reliably elevated. Imaging studies included radiographs, CT scans, and MRIs. All patients were treated with anterior debridement and strut grafting followed by 14.4 days of intravenous antibiotics and delayed instrumented posterior fusions and received 6 weeks of intravenous antibiotics after surgery. RESULTS: All patients had resolution of their infections with no recurrence. There were two deaths. Neurologic deficits resolved in all patients. The diagnosis of pyogenic vertebral osteomyelitis is frequently delayed and presents a significant surgical challenge. The indications for surgical debridement were neurologic compromise, failed medical treatment, soft tissue extension, extensive vertebral body and disc space destruction, and progressive deformity. Many of these patients were severely ill at presentation and required urgent treatment. Anterior debridement and fusion followed by intravenous antibiotics allows for restoration of anterior column support and control of the infection before posterior instrumentation and fusion. CONCLUSION: This study demonstrates that anterior surgical debridement with fusion, followed by a period of intravenous antibiotics and delayed instrumented posterior fusion, is highly effective in the treatment of pyogenic osteomyelitis that has failed medical management.